Compact Multi-user Wideband MIMO System using Multiple-Mode Microstrip Antennas

A complete multiple-input multiple-output (MIMO) communication system with orthogonal frequency-division multiplexing (OFDM) based on multiple excitation modes for a single circular microstrip antenna is introduced. Traditional diversity techniques such as spatial diversity by means of a linear antenna array or polarization diversity by means of a cross-polarized antenna array may prove to be unsuitable in the case of severe restrictions on antenna size and spacing. A microstrip antenna employing multiple modes is found to be comparable to traditional antenna arrays in an urban micro-cell setting as defined by the Third-Generation Partnership Project (3GPP) at a much lower cost in terms of size and spacing. The throughput performance and signal detection of multimode antennas in flat and frequency-selective fading environments is examined subsequently.